The present invention pertains generally to material handling equipment for conveying sheet-like materials and particularly to a system for conveying a paper web for printing, slitting, and cutting.
In the production of preprinted business forms it is known to feed a web from a printer through an accumulator. The web is fed over an infeed roll into an accumulator bin where, during steady-state operation of the system, a loop is formed inside the accumulator bin between the infeed mechanism and an outfeed mechanism. The loop serves many functions including removing the xe2x80x9cbeltxe2x80x9d tension from the outfeed mechanism.
Downstream from the outfeed device, a cutter cuts and stacks the printed forms. For some cutting operations, it is necessary to periodically remove a stack of cut forms from the cutter. In order to do so, the cutter and the outfeed device may have to be temporarily shut down. When the cutter stops, the outfeed device also must stop feeding material from the accumulator. During the stoppage it is preferable for the infeed device to continue to convey material such that the web is continuously fed into the accumulator bin. At this point, the web is still attached to the outfeed device but the portion between the outfeed device and the infeed device is uncontrolled as it enters the accumulator bin. Accordingly, the web piles up in the accumulator bin relatively randomly with cross-folding and wrinkling sometimes occurring.
When the cutter comes back on line, the accumulator outfeed device pulls the web out of the accumulator bin from the bottom of the pile. If the web has cross-folded or wrinkled, there could be a jam in the outfeed device or in the cutter downstream of the accumulator bin.
Accordingly, there is a need for a material handling device that prevents the web from cross-folding or wrinkling during the period when the outfeed device is shut off and the web is accumulating in the accumulator bin.
The present invention meets the above-described need by providing an accumulator system for foldable sheet-like material. The system includes an accumulator bin having a pair of sidewalls, a pair of end walls, a bottom wall, and an open top. An infeed mechanism conveys the material to the accumulator bin. A chute receives the material from the infeed mechanism and guides the material inside the chute. The chute is capable of reciprocating such that the material is guided toward opposite sides of the bottom wall of the bin. The reciprocating motion of the chute causes the material to be folded endwise in alternating fashion. An outfeed mechanism conveys the material to a downstream device such as a cutter. Some downstream cutting operations require an intermittent shut down for removing materials from the cutting station.
The present invention accommodates the downstream flow stoppage by providing for two modes of operation. In a first steady-state condition, the reciprocating chute is stationary and the infeed mechanism and outfeed mechanism form a loop of material in the accumulator bin and convey the material through the system to the downstream device. In a second condition, the outfeed mechanism stops conveying material, and the infeed mechanism continues to convey. The excess material conveyed by the infeed mechanism is folded in the accumulator bin by the reciprocating motion of the reciprocating chute until the outfeed mechanism restarts. Next, the outfeed mechanism pulls material from the bottom of the stack until the loop is formed in the accumulator bin again.